Fair Value Measurements (Tables)

9 Months Ended

Sep. 30, 2018

Fair Value Disclosures [Abstract]

Company's Available-for-Sale Securities by Level within Fair Value Hierarchy

The Company’s available-for-sale securities by level within the fair value hierarchy were as follows (in thousands):

As of September 30, 2018	Level 1		Level 2		Level 3		Total
Cash equivalents:
Money market fund	$	13,761	$	—	$	—	$	13,761
Short-term investments:
Corporate debt securities	—		48,952		—		48,952
U.S. government-related debt securities	—		17,882		—		17,882
Asset-backed securities	—		6,897		—		6,897
Total	$	13,761	$	73,731	$	—	$	87,492
As of December 31, 2017	Level 1		Level 2		Level 3		Total
Cash equivalents:
Money market fund	$	22,398	$	—	$	—	$	22,398
Short-term investments:
Corporate debt securities	—		35,514		—		35,514
U.S. government-related debt securities	—		15,905		—		15,905
Total	$	22,398	$	51,419	$	—	$	73,817